RICHMOND | The Republican Party of Virginia’s state central committee voted Friday to switch from holding a primary to a convention to nominate its 2013 statewide candidates, handing supporters of Attorney General Kenneth T. Cuccinelli II a win and dealing a major blow to Lt. Gov. Bill Bolling, his opponent for the GOP gubernatorial nomination.

Mr. Bolling had lobbied heavily for the party’s governing body to stick with the decision made last fall to nominate the GOP’s candidates for governor, lieutenant governor and attorney general in a statewide primary. But a number of new representatives to comprise the body were elected earlier this year, and the committee reversed its earlier decision.

Proponents of nominating conventions, where a small group of party activists choose the party’s nominee, say they save the state money and keep Democrats and Independents from meddling in party business, since voters do not register by party in Virginia.

But proponents of primaries say that exclusivity is not necessarily a good thing. For example, Mr. Bolling noted that it precludes active duty military personnel from participating.

“This decision creates the impression that our party is an exclusive party, as opposed to an inclusive party, and that is not the message we should be sending to the people of Virginia,” he said.

He also chided the committee for changing the method of nomination in the middle of the primary campaign, calling the move “unprecedented and unfair.”

He added that the move may also create legal questions, but that he would not pursue any type of legal remedy to preserve party unity for the 2012 elections.

Observers have said that a convention would favor Mr. Cuccinelli, saying the electors would be more ardent, involved — and conservative — party activists, with whom the crusading attorney general enjoys wide appeal.

But Mr. Bolling indicated he had no intention of backing down, saying that he has the support of hundreds of party leaders and thousands of grassroots activists “who share my vision of mainstream, results-oriented conservative leadership for families and businesses in our state.”

“With their help, I am confident that we can defy the political pundits and win in a party convention, just like we would have won in a statewide primary,” he said.

Mr. Cuccinelli has said he prefers conventions to primaries, but was not behind the effort to switch the method of nomination for 2013.